ΔE 13.8, fair: the same colour family, but not a straight swap. Phoenix Red is much more muted than Blood Red. They are different kinds of paint: Army Painter Blood Red is a one-coat contrast-style paint and Reaper Phoenix Red is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Phoenix Red is much more muted than Blood Red. They are different kinds of paint.
The same difference applies the other way round: Blood Red is much more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Blood Red on the colour wheel See Phoenix Red on the colour wheel
All matches: Blood Red equivalents · Phoenix Red equivalents